Due to the way the headers are organized a single change in a
AP_GPS backend would trigger a rebuild for most of the files in the
project. Time could be saved by using ccache (since most of the things
didn't change) but we can do better, i.e. re-organize
the headers so we don't have to re-build everything.
This makes internal headers internal and then other libraries only
depend on the AP_GPS.h header.
This commit changes the way libraries headers are included in source files:
- If the header is in the same directory the source belongs to, so the
notation '#include ""' is used with the path relative to the directory
containing the source.
- If the header is outside the directory containing the source, then we use
the notation '#include <>' with the path relative to libraries folder.
Some of the advantages of such approach:
- Only one search path for libraries headers.
- OSs like Windows may have a better lookup time.
This is a complete rewrite of the GPS driver structure, with a static
main driver and separate backend drivers. This will allow proper
support for multiple GPSes, and will allow parameters to be set on the
GPS object
Lucas De Marchi
Gustavo Jose de Sousa
Andrew Tridgell
Craig@3DR